Process for gas cleaning with reclaimed water and apparatus for water reclamation

ABSTRACT

Dispersions comprising water and particulate solids i.e. carbon and ash are produced in at least one gas cooling or scrubbing zone by quench cooling or scrubbing the raw gas stream from a partial oxidation gas generator with water. The dispersions are resolved by liquid extraction in a decanting zone to produce a water layer containing carbon, dissolved gas, and ash, and also a separate dispersion comprising carbon, extractant, and water. Solids-free water, liquid extractant and uncondensed gases are then separated from each other in a distillation and separation operation. Water is removed from a separation vessel in said operation and introduced on to a stripping plate of a flash column containing at least one stripping plate. The solids-containing water from the decanting zone is flashed below said stripping plate and a portion is converted into steam. The steam passes up through holes or bubble caps in the stripping plate and is dispersed through the water contained on said plate. If desired, a portion of the water obtained from blowing-down a gas cooler may be flashed to steam below the stripping plate. Unvaporized water falls to the bottom of the column where a vertical weir separates the flash column into two chambers. Solids settle out of the water in the first chamber and clarified water flows over the weir into the second chamber. Overflow water from the bottom stripping plate is discharged below the water-level in the second chamber by way of a downcomer. Reclaimed water is pumped to said gas cooling and scrubbing zones from the second chamber, and waste water containing solids in the first chamber is discharged from the system. The overhead from the flash column is cooled below the dew point and introduced into said separation vessel.

This application is a continuation-in-part of our application Ser. No.900,951 filed Apr. 28, 1978, now U.S. Pat. No. 4,141,696.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This is a gas cleaning process and includes a flash column apparatus forwater reclamation. More specifically, this process pertains to coolingand scrubbing the raw gas stream from a partial oxidation gas generatorwith reclaimed water and recovering, purifying, and recycling the water.

2. Description of the Prior Art

Synthesis gas mixtures comprising hydrogen and carbon monoxide, andcontaining entrained particulate carbon may be prepared by the partialoxidation of a fossil fuel with a free-oxygen containing gas, optionallyin the presence of a temperature moderator. The hot effluent gas streamfrom the gas generator may be cooled by direct immersion in water in aquench drum such as described in coassigned U.S. Pat. Nos. 2,896,927 and3,929,429. A portion of the entrained solids are removed by the quenchwater. Following the direct quench cooling, the gas is scrubbed withwater to further remove particulates. Alternatively, the hot effluentgas stream may be cooled in a gas cooler such as shown in coassignedU.S. Pat. No. 3,920,717 and then scrubbed with water. The quench-wateror the scrubbing water may be then processed in the manner described incoassigned U.S. Pat. Nos. 2,992,906, 3,097,081, and 4,014,786.

SUMMARY

Particulate solids i.e. carbon soot and ash entrained in the hot raw gasstream from a partial oxidation gas generator are removed by quenchcooling the hot gas stream directly in reclaimed water in a quench drum,or by scrubbing with reclaimed water in a gas scrubbing zone afterindirect heat exchange in a gas cooler or both. By this means, a cleangas stream and a dispersion of particulate solids i.e. carbon and ashare produced. Depending on composition, the clean gas stream is intendedfor use as synthesis gas, reducing gas, or fuel gas.

It is economic to reclaim the water in the aforesaid dispersion byremoving particulate solids and gaseous impurities. The reclaimed watermay be then recycled to the gas quench cooling and scrubbing zones. Thisis done in the subject process by mixing said dispersion of solids andwater together with a liquid extractant. A dispersion comprisingparticulate carbon, extractant, and a small amount of water is formedand in a decanter separates from a dilute water layer which settles tothe bottom of the decanter comprising water, dissolved gases, wastehydrocarbons, ash, and a very small amount of carbon. In a preferredembodiment, heavy liquid hydrocarbon is mixed with the dispersion ofcarbon, extractant, and water from the decanter. In a distillation andseparation operation, the extractant and water are vaporized, condensedand separated by gravity in a separation vessel. At least a portion ofthe solids-free condensed water is withdrawn from the separation vesseland is introduced on to a stripping plate of a flash column containingone or more plates. At least a portion of the extractant from theseparation vessel is recycled to said decanter. Any uncondensed gasesi.e. H₂ S, NH₃, CO.sub. 2 ; and waste hydrocarbons may be removed fromthe top of said separation vessel. Overhead vapors from the flash columnare cooled to condense out water and introduced into said separationvessel.

The stream of dilute water is removed from the bottom of the decanterand is introduced into the flash column below a stripping plate. Aportion of this water is flashed into steam which passes up through thecolumn. The remainder passes down through the column and drops into thereceiving side chamber at the bottom. If desired, a small stream ofblowdown water from a gas cooler in the system, such as after the gasgenerator, may be similarly introduced into the flash column. A portionof this water is flashed into steam and the remainder drops either intothe return water side or into the receiving side chamber at the bottomof the flash column. The flashing steam passes up through gas dispersersi.e. holes or bubble-caps in the stripping plate or plates and stripsthe vaporizable impurities from the water contained on the strippingplate.

The bottom of the flash column is partitioned by means of a verticalweir into said two chambers, i.e. a receiving side and a return waterside. Solids in the water in the receiving side chamber settle to thebottom. The water in the receiving side chamber overflows the weir andfalls into the chamber on the return-water side. Steam strippedover-flow water from the stripping plate or plates flows through adowncomer system that discharges stripped water from plate to plate andfinally exits below the water level in said return water side chamber. Asmall amount of waste water containing solid sediment is removed at thebottom of the receiving side chamber and is discharged from the system.If desired, the waste water may be sent to a water treating plant.Substantially solids-free reclaimed water is pumped out of the returnwater side chamber and recycled to the gas quench cooling tank, or tothe scrubbing zones, or to both places. Optionally, a portion of thiswater may be recycled to the gas generator as a portion of themoderator.

BRIEF DESCRIPTION OF THE DRAWING

The invention will be further understood by reference to theaccompanying drawing.

FIG. 1 of the drawing is a schematic representation of a crossflow sievetype stripping plate showing the direction of flow for liquid and vaporstreams.

FIG. 2 of the drawing is a schematic representation of a preferredembodiment of the process.

DESCRIPTION OF THE INVENTION

In the subject process, a raw gas stream, substantially comprising H₂,CO, and at least one gas from the group H₂ O, CO₂, H₂ S, COS, CH₄, NH₃,N₂, Ar and containing entrained solids i.e. particulate carbon, ash isproduced by partial oxidation of a hydrocarbonaceous fuel with afree-oxygen containing gas, optionally in the presence of a temperaturemoderator, in the reaction zone of an unpacked free-flow noncatalyticpartial-oxidation gas generator. The atomic ratio of free oxygen tocarbon in the fuel (O/C ratio), is in the range of about 0.6 to 1.6, andpreferably about 0.8 to 1.4. The reaction time is in the range of about1 to 10 seconds, and preferably about 2 to 6 seconds. When steam is usedas the temperature moderator the steam-to-fuel weight ratio in thereaction zone is in the range of about 0.1 to 5, and preferably about0.2 to 0.7.

The raw gas stream exits from the reaction zone at a temperature in therange of about 1300° to 3000° F., and preferably 2000° to 2800° F., andat a pressure in the range of about 1 to 250 atmospheres, and preferably15 to 150 atmospheres.

The composition of the raw gas stream leaving the gas generator is aboutas follows, in mole percent on a dry basis: H₂ 60 to 29, CO 20 to 57,CO₂ 2 to 30, CH₄ nil to 25, H₂ S nil to 2, COS nil to 0.1, NH₃ nil to0.1, N₂ nil to 60, and Ar nil to 0.5. Water is present in the gas in therange of about 1 to 75 mole percent. Particulate carbon is present inthe range of about 0.1 to 20 weight % (basis carbon content in theoriginal feed). Ash may be present. Depending on the composition, thegas stream may be employed as synthesis gas, reducing gas, or fuel gas.

The gas generator comprises a vertical cylindrically shaped steelpressure vessel lined with refractory, such as shown in coassigned U.S.Pat. No. 2,809,104. A typical quench drum for cooling the hot effluentstream of gas from the reaction zone to a temperature in the range ofabout 300° F. to 600° F. by direct contact with water is also shown insaid patent. At least a portion of the entrained solids i.e. particulatecarbon, ash, are removed from the process gas stream by the turbulentquench water and a pumpable dispersion of particulate carbon and watercontaining about 0.1 to 4.0 wt. % particulate solids is produced in thequench tank. Any remaining entrained solids may be removed from theprocess gas stream by additional scrubbing with water. A burner, such asshown in coassigned U.S. Pat. No. 2,928,460, may be used to introducethe feed streams into the reaction zone.

Alternatively, the hot effluent gas stream leaving the gas generator maybe cooled to a temperature in the range of about 350° to 750° F. butabove the dew point of water by indirect heat exchange with boiler feedwater in a gas cooler, such as shown and described in coassigned U.S.Pat. No. 3,920,717. The cooled process gas stream is then cleaned byscrubbing with water in a conventional gas scrubbing zone. For example,the gas scrubber as shown in the drawing, or the venturi or jet scrubberas shown in Perry's Chemical Engineer's Handbook, Fifth Edition,McGraw-Hill Book Company 1973, Fig. 20-120 and Fig. 20-121.

In the embodiment shown in the drawing, both methods of cooling theeffluent gas stream from the gas generator are employed. The effluentgas stream is split into two separate gas streams which are processed intwo separate trains. A portion of the hot effluent gas stream is cooledby indirect heat exchange in a gas cooler in the first train; and, theremainer of the gas stream is cooled by direct contact with water in aquench tank in the second train.

A wide range of combustible carbon-containing organic materials may bereacted in the gas generator with a free-oxygen containing gas,optionally in the presence of a temperature-moderating gas, to producethe raw gas stream.

The term hydrocarbonaceous as used herein to describe various suitablefeedstocks is intended to include gaseous, liquid, and solidhydrocarbons, carbonaceous materials, and mixtures thereof. In fact,substantially any combustible carbon-containing organic material, orslurries thereof, may be included within the definition of the term"hydrocarbonaceous". For example, there are (1) pumpable slurries ofsolid carbonaceous fuels, such as particulate carbon dispersed in avaporizable liquid carrier, such as water, liquid hydrocarbon fuel, andmixtures thereof; and (2) gas-liquid-solid dispersions, such as atmoizedliquid hydrocarbon fuel and particulate carbon dispersed in atemperature moderating gas.

The term liquid hydrocarbon, as used herein to describe suitable liquidfeedstocks, is intended to include various materials, such as liquefiedpetroleum gas, petroleum distillates and residua, gasoline, naphtha,kerosine crude petroleum, asphalt, gas oil, residual oil, tar-sand oiland shale oil, coal derived oil, aromatic hydrocarbons (such as benzene,toluene, xylene fractions), coal tar, cycle gas oil fromfluid-catalytic-cracking operations, furfural extract of coker gas oil,and mixtures thereof.

Gaseous hydrocarbon fuels, as used herein to describe suitable gaseousfeedstocks, include methane, ethane, propane, butane, pentane, naturalgas, coke-oven gas, refinery gas, acetylene tail gas, ethylene off-gas,and mixtures thereof. Solid, gaseous, and liquid feeds may be mixed andused simultaneously; and these may include paraffinic, olefinic,acetylenic, naphthenic, and aromatic compounds in any proportion.

Also included within the definition of the term hydrocarbonaceous areoxygenated hydrocarbonaceous organic materials including carbohydrates,cellulosic materials, aldehydes, organic acids, alcohols, ketones,oxygenated fuel oil, waste liquids and by-products from chemicalprocesses containing oxygenated hydrocarbonaceous organic materials, andmixtures thereof.

The hydrocarbonaceous feed may be at room temperature, or it may bepreheated to a temperature up to as high as about 600° to 1200° F. butpreferably below its cracking temperature. The hydrocarbonaceous feedmay be introduced into the gas-generator burner in liquid phase or in avaporized mixture with the temperature moderator.

The need for a temperature moderator to control the temperature in thereaction zone depends in general on the carbon-to-hydrogen ratios of thefeedstock and the oxygen content of the oxidant stream. A temperaturemoderator may not be required with some gaseous hydrocarbon fuels,however, generally one is used with liquid hydrocarbon fuels and withsubstantially pure oxygen. Steam may be introduced as a temperaturemoderator in admixture with either or both reactant streams.Alternatively, the temperature moderator may be introduced into thereaction zone of the gas generator by way of a separate conduit in theburner. Other temperature moderators include: CO₂, N₂, a cooled portionof the effluent gas stream from the gas generator, and mixtures thereof.

The term free-oxygen containing gas as used herein means air,oxygen-enriched-air i.e. greater than 21 mole % O₂, and substantiallypure oxygen, i.e. greater than about 95 mole % oxygen (the remainderusually comprising N₂ and rare gases). Free-oxygen containing gas may beintroduced by way of the partial-oxidation burner at a temperature inthe range of about ambient to 1800° F.

The raw synthesis gas exiting from the reaction zone of the gasgenerator is preferably split into two streams which are thensimultaneously processed in two separate trains. In the first train nowater-gas shifting takes place, whereas in the second train water-gasshifting of the crude gas stream does take place. By this means, theproduct gas from the second train has a greater mole ratio of H₂ /COthan that produced in the first train.

The split of the raw synthesis gas between the two trains may becalculated by material and heat balances. The calculated split may bethen adjusted, if necessary, during actual operation. Accordingly, saidcalculations take into consideration the compositions of thehydrocarbonaceous fuel and the raw synthesis gas, the amount and desiredcomposition of the clean purified synthesis gas product stream, thedesired amount of hydrogen rich product gas, the desired amount andefficiency of the catalytic water-gas shift conversion, and the desiredamount of by-product steam. For example, from about 0 to 100 volume %,such as about 5 to 95 volume % of the raw gas stream leaving thereaction zone of the gas generator may be directly introduced into aquench drum containng water in the second train. When the feed to thegas generator includes a high ash fuel i.e. coal about 5-10 volume % ofthe raw gas stream may be introduced into the quench drum to carry theslag. The remainder of the synthesis gas from the gas generator may bepassed through an insulated transfer line, and directly into a gascooler in the first train. There the hot gases are passed in indirectheat exchange with boiling water, thereby cooling the gas stream to atemperature in the range of about 350° to 750° F. while simultaneouslyproducing by-product steam.

The by-product steam may be used elsewhere in the process whererequired. Further, it may be produced at a pressure which is greaterthan that in the gas generator. Portions of the by-product steam may beused--for example, as the temperature moderator in the gas generator, asa carrier for the hydrocarbonaceous fuel, or as the working fluid in anexpansion turbine; i.e. turbocompressor or turboelectric generator. Thesteam may also be used to power an air-separation unit that produces thesubstantially pure oxygen used in the gas generator.

The amount of solid particles, i.e. selected from the group: particulatecarbon, ash, and mixtures thereof, entrained in the raw gas streamleaving the reaction zone is dependent on the type of hydrocarbonaceousfuel and the atomic ratio (O/C) in the reaction zone. A minimum amountof entrained particulate carbon i.e., about 1-2 wt. % (basis weight of Cin the hydrocarbonaceous feed), is recommended to increase the life ofthe refractory lining the gas generator when the feed contains Ni and Vimpurities.

The quench drum in the second train, also known as the quench tank, islocated below the reaction zone of the gas generator. The split streamof raw gas which it receives for cooling and cleaning carries with itsubstantially all of the ash and a substantial part of theparticulate-carbon soot leaving the reaction zone of the gas generator.A dispersion is produced in the quench tank comprising quench water,about 0.1 to 4.0 wt. % of particulate solids i.e. carbon and ash, and aminor amount of water soluble impurities. Any unburned inorganic solidssuch as coarse ash from solid fuels and refractory may accumulate at thebottom of the quench tank. Periodically, this material may be removed asa water slurry through a conventional lock-hopper system. Optionally,water may be separated from this slurry by conventional means i.e.gravity settling, flotation, centrifuge, or filtration. The water may berecycled in the process for further purification along with the quenchwater.

To prevent plugging any downstream catalyst beds, a secondary gascleaning zone preferably follows the quench tank in the second train.The secondary gas cleaning zone may include conventional orifice andventuri scrubbers and sprays by which the process gas stream is scrubbedwith reclaimed water. The scrub water containing less than about 0.1 wt.% solids is preferably recycled to the quench tank. By this means theamount of solid particles in the process gas stream may be reduced toless than about 3 parts per million (PPM), and preferably less thanabout 1 ppm. The mole ratio of H₂ O/CO in the process gas stream in thesecond train may be increased to a value in the range of about 2 to 5,and preferably 2.5 to 3.5 by vaporizing water during the quenching andscrubbing steps that may follow. This ratio is suitable for the nextstep in the second train, in which the water-gas shift reaction takesplace.

Thus, after leaving the secondary gas scrubbing zone, the soot-free gasstream in the second train is preferably introduced into a conventionalcatalytic water-gas shift reaction zone at an inlet temperature in therange of about 350° to 775° F. CO and H₂ O are reacted over aconventional water-gas-shift catalyst which may comprise iron oxidemixed with Cr oxide and promoted by 1 to 15 wt. % of an oxide of anothermetal, such as K, Th, U, Be or Sb. Reaction occurs at about 500° to1050° F. Alternatively, cobalt molybdate on alumina may be used as thewater-gas shift catalyst at a reaction temperature in the range of about500° to 900° F. Co-Mo catalysts comprise, in weight percent: CoO 2-5,MoO₃ 8-16, MgO nil-20, and Al₂ O₃ 59-85. A low-temperature shiftcatalyst for use with sulfur-free gas streams comprises a mixture ofcopper and zinc salts or oxides in a weight ratio of about 1/2 to 3parts by weight zinc to 1 part copper.

Next, substantially all of the H₂ O is removed from the gas stream inthe second train. For example, the clean gas stream may be cooled to atemperature below the dew point of water by conventional means tocondense out and to separate H₂ O. If desired, the gas stream may besubstantially dehydrated by contact with a desiccant, such as alumina.With oxygen gasification, a clean shifted product gas stream is therebyproduced having the following composition in mole %: H₂ 98 to 60, CO nilto 5, CO₂ 15 to 40, CH₄ nil to 5, H₂ O nil to 5, Ar nil to 0.5, N₂ nilto 1, H₂ S nil to 2, and NH₃ nil to trace.

The cooled process gas stream leaving the gas cooler in the first trainis scrubbed with water in a conventional gas scrubbing zone to removeparticulate solids i.e. carbon and ash. A dispersion of scrubbing watercontaining about 0.1 to 4.0 wt. % of particulate solids, and a minoramount i.e. in PPM (parts per million) of water soluble impurities isproduced. The gas stream leaving the cleaning zone in the first train isoptionally cooled below the dew point and is then introduced into aknockout or separation vessel. With oxygen gasification, a cleanunshifted product gas stream is thereby produced having the followingcomposition in mole %: H₂ 60 to 29, CO 20 to 57, CO₂ 2 to 30, CH₄ nil to25, H₂ O nil to 20, H₂ S nil to 2, COS nil to 0.1, NH₃ nil to trace, N₂nil to 1 and Ar nil to 0.5.

As previously described, the gas cooler cools the hot raw synthesis gasby indirect heat exchange with boiler feed water. A small blowdownstream may be periodically taken from the water being vaporized tocontrol the buildup of dissolved solids in the water. The blow-downwater leaving the gas cooler may contain a minor amount (in PPM) ofmetal salts i.e. chlorides, sulfates, and phosphates. The blow-downwater stream leaves the gas cooler i.e. waste-heat boiler at atemperature in the range of about 300° to 600° F., say about 550° F. Thepressure corresponds to that of the steam produced in the boiler.

The dispersions of water-particulate solids from the quench tank in thesecond train, or from the scrubbing zone in the first train, or fromboth are introduced in admixture with a suitable liquid organicextractant such as light liquid hydrocarbons i.e. naphtha into a carbonseparation zone. Conventional horizontal and vertical decanters may beemployed. The liquid organic extractant may be added in one or twostages. A description of suitable vertical decanters, liquid organicextractants, and methods of operation are described in coassigned U.S.Pat. No. 4,014,786, which is incorporated by reference.

In one embodiment of the subject process, a two-stage decantingoperation is used. A first portion of the liquid organic extractantseparated downstream in the process is mixed with all of thecarbon-water dispersion. The amount of liquid organic extractant issufficient to resolve the carbon-water dispersion. This amount may be inthe range of about 1.5 to 15 lbs. of extractant per lb. of carbon. Themixture is then introduced into the first stage of a two-stage decantingoperation. Simultaneously, a second portion of the liquid organicextractant in an amount sufficient to produce a pumpable liquid organicextractant-carbon-water dispersion having a solids content in the rangeof about 0.5 to 9 wt. % is introduced into the second stage.

Suitable liquid organic extractants that form dispersions withparticulate carbon which are lighter than water include: (1) lightliquid hydrocarbon fuels having an atmospheric boiling point in therange of about 100° to 750° F., density in degrees API in the range ofover 20 to about 100, and a carbon number in the range of about 5 to 16;(2) a mixture of substantially water insoluble liquid organicby-products from an oxo or oxyl process; and (3) mixtures of types (1)and (2). Examples of type (1) liquid extractants include butanes,pentanes, hexanes, toluol, natural gasoline, gasoline, naphtha, gas oil,their mixtures and the like. Ingredients in the mixture comprising type(2) extractants include at least one alcohol, at least one ester and atleast one constituent from the group consisting of aldehydes, ketones,ethers, acids, olefins, and saturated hydrocarbons.

The particulate solids in the water dispersions introduced into thedecanter comprises carbon and ash. The particulate carbon is in the formof free-carbon black or soot. The Oil Absorption No. of the carbon soot,as determined by ASTM Method D-281, is greater than 1 and usually variesfrom 2 to 4 cc of oil per gram of C. The inorganic ash from the oil inthese dispersions comprises metals and the sulfides. For example, forpetroleum derived fuels these components may be selected from the groupNi, V, and Fe, and mixtures thereof. Further, for such fuels the amountof soluble impurities in the dispersions of water-particulate solidscomprise in parts per million (PPM): ammonia 0 to 10,000; formate 0 to10,000; sodium chloride 0 to 5000; nickel 0 to 25; iron 0 to 150;sulfide 0 to 500; and cyanide 0 to 100.

One or two-stage decanters may be employed. The decanter is operated ata temperature in the range of about 180° to 500° F. and preferably above250° F. The pressure in the decanter is basically set by thetemperature. The pressure must be high enough to keep the liquid organicextractant in a liquid phase. Thus, when the decanter bottoms outlettemperature is 300° F., and the liquid organic extractant is naphtha,the pressure in the decanter may be at least 300 psia. The total amountof liquid organic extractant that may be introduced into a one ortwo-stage decanting operation is in the range of about 10 to 200 times,such as 30 to 70 times, the weight of the particulate carbon in thecarbon-water dispersion. The dispersion of water and particulate solidsis resolved in the decanter. A stream of water containing about 100 to500 parts per million by weight of particulate carbon and about 20 to 60wt. % of the ash separates out by gravity and leaves at the bottom ofthe decanter. Most of the other impurities in the dispersions ofwater-particulate solids that enter the decanter in the feed, asmentioned previously, are also included in this water stream that leavesfrom the bottom of the decanter. This dilute water dispersion leaves thedecanter at a temperature in the range of about 180° to 500° F., say250° to 350° F. and a pressure of about 150 to 1000 psig, say about 250to 500 psig. The water may contain gaseous impurities selected from H₂S, CO₂ and NH₃. The residence time in the decanter may be in the rangeof about 2 to 20 minutes, say 6 to 15 minutes.

A dispersion of carbon-liquid extractant containing about 0.5 to 9 wt. %of particulate carbon and about 0.5 to 10 wt. % of carry-over water isremoved from the top of the decanter. In a preferred embodiment, thisstream is mixed with a heavy liquid hydrocarbon fuel i.e. fuel oil,crude oil having a gravity in degrees API in the range of about -20 to20. The mixture is then introduced into a distillation column. Theamount of heavy liquid hydrocarbon fuel, as previously described, iskept to a minimum. This amount should be sufficient only to form apumpable bottoms slurry with the particulate carbon separated from saidcarbon-extractant dispersion. The aforesaid pumpable bottoms slurry mayhave a carbon content of about 0.5 to 25 wt. percent and preferably 4 to8 wt. percent. The slurry of carbon and heavy liquid hydrocarbon isremoved from the bottom of the distillation column and sent to the gasgenerator as a portion of the feed. The overhead vapors from thedistillation column are cooled to a temperature below the dew points ofthe liquid organic extractant and water. The liquid organic extractantand water containing any dissolved acid-gases and a minor amount ofhydrocarbons extracted by the water from the liquid organic extractantand the heavy hydrocarbonaceous liquid settle out and are separated in aseparation vessel. When emulsion forming impurities are present in theheavy liquid hydrocarbon fuel or in the liquid organic extractant, bycooling the overhead from the distillation column to a temperature abovewhich the aqueous emulsion does not form, say at a temperature greaterthan 140° F., the formation of troublesome emulsions in the separatingtank may be avoided. At least a portion, and preferably all, of theliquid organic extractant is removed from the separation vessel and isrecycled to the inlet of the decanter where it is introduced with theincoming dispersion of water and particulate carbon. Optionally, aportion of the liquid organic extractant may be recycled back to thedistillation column as reflux. At least a portion of the water layer isremoved from the bottom of the separating tank following thedistillation column at a temperature in the range of about 80° to 150°F. and a pressure in the range of about 0 to 50 psig. Optionally, aportion of the water from the separation vessel may be introduced, inliquid or vapor phase, into the gas generator as a portion of thetemperature moderator. At least one uncondensed acid-gas from the groupH₂ S, COS, and CO₂ if present may be removed from the top of theseparation vessel.

In one embodiment the hydrocarbonaceous feed to the gas generatorcomprises liquid hydrocarbon distillate substantially comprising aboutC₃ to about C₁₀ hydrocarbons and a dispersion of particulate carbon andsaid liquid hydrocarbon distillate. In this case the liquid hydrocarbondistillate is also employed as the liquid organic extractant in thedecanter. The distillation column may be thereby eliminated, and theoverhead stream of carbon-extractant dispersion from the decanter may bethen introduced, with or without heat exchange, into the gas generatoras a portion of the feedstock.

Advantageously, water employed in the subject process for quench coolingand scrubbing the process gas stream is reclaimed by removingparticulate solids and gaseous impurities in a flash column. Thereclaimed water is then recycled to the gas quenching and scrubbingzones. The water flash column comprises: an upright column; at leastone, such as 1-5 and preferably one horizontal stripping plate spacedwithin said column for holding water to be stripped, each platecontaining dispersive means for dispersing steam through the water onsaid stripping plate, and over-flow and down-flow means for continuouslydischarging the steam stripped water from plate to plate and finallyinto a return water-side chamber below; a vertical weir separating thecolumn at the bottom into a first or receiving-side chamber filled withwater, and said second or return water-side chamber for holding thewater that overflows said vertical weir from said first chamber and thesteam stripped water that overflows the stripping plate in a singleplate column or the bottom stripping plate in a multiplate columnwhereby the water is discharged below the level of the liquid in saidsecond chamber; inlet means for flashing at least one stream of watercontaining particulate solids into the space below the bottom strippingplate and above said first or second chambers, and inlet means forintroducing at least one stream of water containing substantially nosolids on to at least one stripping plate, and preferably the topstripping plate; outlet means for removing from the column an overheadstream of vapors comprising at least one member of the group H₂ O, CO₂,H₂ S, NH₃, and hydrocarbons; outlet means at the bottom of said towerfor removing from said second chamber a stream of reclaimed water ofsubstantially reduced solids content; and outlet means for removing fromsaid first chamber a stream of waste water containing particulatesolids.

The top horizontal stripping plate in the flash-tower is preferablyspaced from about 1/3 to 3/4 of the height of the column. Conventionalcrossflow plates, including bubble-cap, sieve, or valve equipped with atleast one downcomer may be employed. Gas dispersers include perforationsin the plates or bubble caps. Perforated plates include sieve plates orvalve plates. For example, sieve-plate dispersers contain drilled orpunched holes 1/8 to 1/2 inch diameter. Liquid is prevented from flowingdown through the perforation by the upward flowing action of the vapor.Thus, the pressure in the tower below a stripping plate is about 1 to 3psig greater than the pressure in the tower above the stripping plate.With bell caps and tunnel caps, the vapor flows up through a centerriser in the plate, reverses flow under the cap, passes downward throughthe annulus between the riser and cap, and finally passes through theliquid on the plate through a series of peripheral openings or slots inthe lower side of the cap.

The downcomer zones generally occupy about 5 to 30 percent of the totalcross section, such as 5 to 15% for segmental downcomers, as shown inthe drawing. Included is a vertical weir which extends upwards from thestripping plate. Steam stripped water continuously builds-up on theplate and overflows said weir. Additional information on stripping platedesign may be obtained from Chemical Engineers Handbook, Robert H. Perryand Cecil H. Chilton, Fifth Edition 1973 McGraw-Hill Book Co. Page 18-3to 18-19.

The overhead stream of vapors leaves the water-flash column at atemperature in the range of about 212° to 275° F. This stream is cooledbelow the dew point and water and liquid hydrocarbons are condensed outand are separated from the uncondensed gases in a separation vessel.Advantageously, in the subject embodiment, the separation vessel is thesame vessel that is used to receive the cooled stream of water, liquidorganic extractant, and uncondensed gases from the distillation column.Any uncondensed vapors from the group H₂ S, CO₂, NH₃, hydrocarbons, andmixtures thereof are removed from the top of the separation vessel.Clear water is drawn off from the bottom of the separation vessel and isrecycled to the water flash column where it is introduced on to astripping plate at a temperature in the range of about 80° to 175° F. Ina multiplate flash column, this water stream is preferably introduced onto the top plate.

In the operation of the flash column water streams containingsubstantially no solids i.e. solids-free are introduced on to astripping plate, i.e., preferably the top plate. Solids containing waterstreams and blow-down water streams, if any, are flashed into the columnto produce steam in the space below the bottom stripping plate and abovethe two chambers in the bottom of the column. Thus, the dilutedispersion of water and particulate solids from the bottom of thedecanter, and at substantially the same conditions of temperature andpressure less ordinary losses in the line, is passed through a pressurereducing means such as an expansion valve. The pressure is dropped toabout 0 to 30 psig, and for example up to 10 wt.%, say about 1-7 wt.%,is flashed into steam. The stream is introduced into the flash columnbelow the stripping plate at the bottom of the column and in the spaceabove the receiving side chamber. The steam passes up through the gasdispersers in the perforated plate, as previously described. Theunvaporized portion of said stream and the dispersed solids fall intothe receiving side chamber. If desired, a portion of the blow-down waterstream from the gas cooler following the gas generator may be similarlypassed through a pressure reducing means, such as an expansion valve,and reduced to a pressure in the range of about 0 to 30 psig prior tobeing introduced into the flash column. A portion of the water in thisstream is flashed into steam i.e. up to 25 wt.%, say 5 to 15 wt.%. Thisstream contains practically no particles and may be introduced into theflash column below the bottom stripping plate and in the spacepreferably, above the return water side chamber. Optionally, theblow-down water stream may be flashed into the space above the receivingside chamber. The solids-free water from the separator following thedistillation column is introduced on to a stripping plate in the flashcolumn. Preferably, this solids-free water stream is introduced in thespace at the upper part of the flash column above the top tray. Freshwater make-up may be introduced into the return water side chamber ofthe flash column.

Reclaimed water containing from about 0 to 0.05 wt.% particulate solidsmay be withdrawn from the return water side chamber at a temperature inthe range of about 212° to 275° F. and a pressure in the range of about0 to 30 psig and recycled to the scrubbing zone in the first train, thescrubbing and quench zones in the second train, or to both trains.Optionally, a portion of this water may be recycled to the gasgenerator. A stream of waste water at substantially the same temperatureand pressure as the reclaimed water may be removed from the receivingchamber and discharged from the system. The waste water stream maycontain about 0 to 0.2 wt.% particulate solids, and the followingsoluble impurities in PPM: ammonia 0 to 10,000; formate 0 to 10,000;sodium chloride 0 to 5,000; sulfide 0 to 500; nickel 0 to 25; iron 0 to150, and cyanide 0 to 100.

DESCRIPTION OF THE DRAWING

A more complete understanding of the invention may be had by referenceto the accompanying drawing. FIG. 1 is a fragmental schematicrepresentation of a vertical cylindrically shaped flash-tower 1 takenaround stripping plate 2. Small diameter holes 3 are drilled in plate 2and the rate of flow of vapors 4 up through the holes in plate 2prevents the water on plate 2 from passing down through the holes. Bythis means the vaporizable impurities may be stripped from the watercontained on plate 2. Horizontal plate 2 is substantially round exceptfor one side that has attached a vertical chordal weir 5 that dischargesinto segmental or round downcomer 6. A solids-containing water stream inline 7 is passed through pressure reducing valve 8 and line 9, inlet 10and is flashed into flash column 1. Substantially solids-free impurewater is passed through line 11 and inlet 12 on to plate 2. Strippedwater overflows weir 5 and flows down through downcomer 6 to areturn-water side chamber (not shown in FIG. 1).

With reference to the FIG. 2, unpacked, free-flow noncatalyticrefractory lined synthesis gas generator 15, as previously described hasan annulus-type burner 16 mounted in its upper inlet port 17 along thevertical axis. The feed streams are introduced into the reaction zone 18of the gas generator by way of burner 16. They include a free oxygencontaining gas stream which passes through line 19, and the centralconduit (not shown) of the burner, a stream of steam which passesthrough lines 20 and 21, and a stream of hydrocarbonaceous fuel whichpasses through lines 22 and 21. The latter two streams are mixedtogether in line 21 and the mixture is then passed through the annuluspassage (not shown) in burner 16.

The effluent stream of gas leaves the reaction zone and passes throughexit passage 23 and directly into an insulated chamber 24 where theeffluent gas stream is split into two gas streams. One split stream ofraw synthesis gas passes through insulated transfer line 25 into thefirst train of process steps which ends with the production of a streamof unshifted product gas in line 26. The remainder of the effluent gasstream comprises the second split stream. The second split stream isprocessed in the second train which terminates with the production of astream of shifted product gas in line 27. The mole ratio H₂ /CO of theshifted gas stream 27 is greater than the mole ratio H₂ /CO of unshiftedgas stream 26.

Returning now to the first train and the first split stream of raw gasin transfer line 25, this gas stream is passed through inlet 29 of gascooler 30 where it is cooled by indirect heat exchange with a stream ofboiler feed water from line 31. The boiler feed water passes throughinlet 32 and leaves as steam through outlet 33 and line 34. The cooledgas stream leaves through outlet 35, line 36, inlet 37, dip tube 38 andis contacted with water 39 in the bottom section 40 of gas scrubber 41.The process gas stream passes up through the water in the annularpassage made by the inner surface of concentric pipe 42 and the outersurface of dip tube 38 and leaves by outlet 43 and line 44. The processgas stream then passes through venturi scrubber 45 where it is washedwith water from line 46. It is then passed up through upper chamber 47of gas scrubber 41. Water from line 48 and inlet 49 enters upper chamber47 and cascades down over a series of trays 50 in reverse flow and incontact with the process gas stream which is simultaneously passing upthrough the chamber. Water from the bottom of upper chamber 47 passesthrough outlet 51, line 52, and enters bottom chamber 40 through inlet53. Any entrained solids i.e. particulate carbon and ash are therebyscrubbed from the process gas stream and pass with the water throughlines 57-59, and inlet 60 into separation vessel i.e. decanter 61.

The cleaned process gas stream leaving gas scrubber 41 through line 62is cooled below the dew point in heat exchanger 63 by indirect heatexchange with cold water entering through line 64 and leaving by line65. The cooled stream passes through line 66 into separation vessel 67where the condensed water is removed at the bottom by way of line 68. Bymeans of pump 69, the condensate is passed through lines 70, 71, 48, andinlet 49 into gas scrubber 41. A portion is by-passed through line 46into venturi 45, as previously described. The cleaned unshifted productgas stream leaves separator 67 through line 26.

Returning now to the second train, the remainder of the gas streampasses through line 73, dip tube 74 and is quench cooled in a pool ofwater 75 contained in the bottom of quench tank 76. A dispersion ofwater and dispersed solids i.e. particulate carbon and ash is removedthrough outlet 79 and line 80 and sent to a carbon recovery and waterreclaiming section to be further described. Periodically, ash which maybuild up in the bottom of quench vessel 76, may be removed with somewater through bottom outlet 81, line 82, valve 83, and line 84 and sentto a conventional solids separation and recovery zone. Optionally, aconventional lock-hopper system (not shown) may be used to remove thesolids.

The dispersion of particulate solids and water in line 80 is cooled inheat exchanger 85 by indirect heat exchange with reclaimed water fromline 86. It is then passed through line 87, and mixed in line 58 withthe particulate solids-water dispersion coming from gas scrubber 41 andline 57 in the first train. The mixture is then passed into decanter 61by way of lines 59, and inlet 60.

After being quench cooled and partially cleaned with water in quenchtank 76, the process gas stream in the second train passes up throughdraft tube 77 and leaves by outlet 89, line 90, and is scrubbed inorifice scrubber 91 with water from line 92. The process gas stream inline 93 enters separation vessel 94 by way of a dip tube 95. There,excess water drops out and leaves by way of line 96. This water streamis then recycled to quench tank 76. Before leaving separation vessel 94,by way of line 97, the process gas stream is sprayed with water 98 fromline 99.

The cleaned process gas stream saturated with water in line 97 ispreheated in heat exchanger 100 by indirect heat exchange with theshifted stream of gas leaving catalytic water-gas shift conversion zone101 through line 102. The feed stream enters shift conversion zone 101through line 103, and at least a portion of the CO and H₂ O in theprocess gas stream react therein to produce H₂ +CO₂. The resulting cleanH₂ -rich gas stream is cooled in heat exchanger 100 and is then passedthrough line 104 into gas cooler 105 where the temperature of gas streamis dropped below the dew point by indirect heat exchange with water. Forexample, boiler feed water in line 106 may be preheated in heatexchanger 105, passed through line 107, and then introduced into gascooler 30 by way of line 31 where it is converted into steam. The cooledH₂ -rich gas stream is passed through line 108 into condensate separator109 where condensed water is drawn off at the bottom through line 110and clean H₂ -rich product gas exits through line 27 at the top.

The various solids-containing water streams or dispersions produced inthe first and second trains are introduced into the carbon-recovery andwater-reclaiming section of the process. Liquid organic extractant 115,such as naphtha in separation vessel 116, is passed through lines 117 to120, and mixed in line 59 with the dispersion of water, particulatecarbon, ash, and other impurities from line 58. Any required make-upliquid organic extractant may be introduced into the system through line121, valve 122, and line 123. If desired, the liquid organic extractantin line 118 may be preheated by indirect heat exchange with the overheadfrom distillation column 137 in line 140. A portion of the liquidextractant in line 118 may be passed through line 125 into distillationcolumn 137 as reflux. Sufficient liquid extractant is added to thedispersion to separate the particulate carbon from the water. Themixture passes through inlet 60, as previously mentioned, and passes upthrough an annular passage (not shown) that exists between concentricouter pipe 126 and inner pipe 127 in decanter 61, and then out throughthe lower horizontal radial nozzle 128. Simultaneously, in the secondstage, a larger amount of liquid extractant from line 119 is passedthrough line 129, inlet 130, inner pipe 127, and upper horizontal radialnozzle 131. A dispersion comprising liquid extractant, particulatecarbon, carry-over water, and other impurities is removed through line132 and mixed in line 133 with heavy liquid hydrocarbon fuel oil fromline 134. The mixture is heated in heater 135, and passed through line136 into distillation column 137, equipped with reboiler 138. A slurryof heavy liquid hydrocarbon and particulate carbon is removed throughline 139 at the bottom of column 137 and introduced into gas generator15 as a portion of the fuel. The hot vapors in line 140 are passed intoa cooler 141 and cooled below the dew point. The mixture of uncondensedgases, liquid extractant, and water is passed through line 142 intoseparator 116. Liquid organic extractant 115 floats on a layer of water143 in separation vessel 116. Uncondensed gases are removed through line144. The gas stream comprises at least one gas selected from the groupH₂ S, NH₃, CO₂, and hydrocarbon vapors and may be introduced into aClaus operation (not shown) for recovery of sulfur, or sent to flare. Atleast a portion of the water is removed through line 145. By means ofpump 146, the water is pumped through line 147 on to stripping plate 148of flash column 149. Optionally, a portion of the water may be passedthrough line 170, valve 171, and line 172 for use in gas generator 15.

Stripping plate 148 is substantially round except for one chordal sideand is equipped with a plurality of vapor risers 150 and bell-caps 152.Steam stripped water 152 on plate 148 overflows vertical chordal weir153 attached to the end of the otherwise round plate 148. The strippedwater falls into segmental downcomer 154 and discharges beneath thewater level 155 in return-water side chamber 156. Vertical weir 157divides the bottom of flash-column 149 into return-water side chamber156 and receiving side chamber 158. That portion of the water which isnot flashed builds up in receiving side chamber 158 until water level159 is reached when it overflows weir 157. Deflection shield or baffle160 prevents unflashed water from dropping into chamber 156. Make-upwater may be added through line 161.

In operation, the stream of water, dissolved gases i.e. H₂ S, NH₃, CO₂,and particulate solids i.e. particulate carbon and ash separated indecanter 61 is introduced into flash column 149, below stripping plate148 by way of line 162, pressure reducing valve 163, and line 164. Ifdesired, for control of the total dissolved solids in the boiler feedwater, a stream of water produced by blowing down a minor portion of thewater in gas cooler 30 is also introduced into flash column 149 belowstripping plate 148 and preferably below baffle 160 by way of line 165,pressure reducing valve 166, line 167 and internal pipe 168. At least aportion of stream 164 is flashed into steam and the remainder falls intoreceiving side chamber 158. There are practiaally no particulates in thewater in line 168. At least a portion of this stream is flashed intostream and the remainder falls into chamber 156.

Water 143 at the bottom of separation vessel 116 contains dissolvedgases i.e. H₂ S, NH₃, CO₂ and waste hydrocarbons and is pumped by meansof pump 146 on to stripping plate 148 in flash column 149 by way oflines 145 and 147. Steam in the space under plate 148 passes up throughriser 150 and is deflected by bell-cap 151 through the water containedon stripper plate 148. The vapors leaving flash column 149 through line175 are cooled below the dew point of water in cooler 176 and are passedthrough line 177 into separation vessel 116. Pipe 178 on the inside ofvessel 116 discharges the gas stream below the surface of the pool ofwater 143.

The purified reclaimed water from the bottom of return-water sidechamber 156 in water-flash column 149 is pumped by means of pump 181 togas scrubber 41 in train I by way of lines 182, 183, 184, 71, 48, inlet49, and also line 46 to venturi scrubber 45. A second stream of purifiedreclaimed water from chamber 156 is pumped through lines 182, 183, 86,heat exchanger 85, lines 185, 186, 99 to spray scrubber 94, and alsoline 92 to orifice scrubber 91.

Waste water containing solids is removed from the receiving-side chamber158 and is discharged from the system through line 190.

EXAMPLE

The following example illustrates a preferred embodiment of the processof this invention as shown in the drawing which pertains to a partialoxidation process for the simultaneous production of two clean streamsof gas in two separate trains, one gas stream being shifted and theother being unshifted. Both gas streams are cleaned by contact withreclaimed water produced in the process. While preferred modes ofoperation are illustrated, the Example should not be construed aslimiting the scope of the invention. The process is continuous and theflow rates are specified on an hourly basis for all streams ofmaterials.

162,356 lbs. of a vacuum resid having a gravity of 2.0 degrees API, anUltimate Analysis in weight percent as follows: C 83.45, H 10.10, N0.35, S 5.50, and O 0.60, an ash content of 0.3 weight % max. comprisingin parts per million by weight of the elements vanadium 300 and nickel50, and a salt content of 10.0 max. pounds per thousand barrels, aremixed with 2765 pounds of recycled unreacted particulate carbonrecovered downstream in the process to produce a pumpable dispersion ofparticulate carbon and petroleum oil. The oil-carbon dispersion ispumped through a heater where it is brought up to a temperature of 540°F. and a pressure of 1165 psig. The dispersion is then mixed with astream of 64,942 lbs. of steam at a temperature of 574° F. and apressure of 1165 psig from line 20 in the drawing.

The oil-carbon-steam mixture is passed through the annulus of anannulus-type burner which is located in the upper end of a conventionalvertical refractory lined free-flow noncatalytic unpacked synthesis gasgenerator 15.

Simultaneously, a stream of 171,033 lbs. of substantially pure oxygeni.e. 99.5 mole % O₂ from line 19 is passed through the center passage ofthe burner. The two streams impinge, mix and the partial oxidation andother related reactions then take place in the reaction zone of the gasgenerator.

A stream of 8.69 million standard cubic feet (SCF measured at 60° F.,14.7 psia) of raw gas leave the reaction zone of the gas generator at atemperature of 2596° F. and a pressure of 1050 psig. The composition ofthe raw gas at the exit 23 from reaction zone 18 is shown in Column 1 ofTable I. About 2765 lbs. of unreacted carbon plus ash are entrained inthe raw synthesis gas.

The raw effluent gas stream leaving the reaction zone is split into twostreams at 24: 5.65 million SCF of raw gas are processed in a firsttrain where no water-gas shift reaction i.e. no shifting takes place;and the remainder, 3.04 million SCF of raw gas are simultaneouslyprocessed in the second train where shifting takes place. The raw gasstream leaving gas cooler 30 in line 36 of the first train is cleaned ingas scrubber 41. After substantially all of the entrained carbon and ashare scrubbed from the raw gas stream and the gas stream is cooled belowthe dew point to condense out substantially all of the water, thecomposition of the unshifted product gas stream in line 26 is shown incolumn 2 of Table I.

About 21,540 gallons per hr. (GPH) of a water dispersion containingabout 1 wt. % of particulate solids are removed from gas scrubber 41through line 57 at a temperature of 310° F. and a pressure of 860 psig.The solids content of this water stream is reduced and the water isreclaimed for recycle to gas scrubber 41 in the manner to be furtherdescribed.

Returning now to the second split stream of raw synthesis gas whichcomprises the remainder of the stream of raw gas stream leaving thereaction zone. By passing all of the raw gas from the reaction zonethrough a passage of reduced diameter at 23, the rate of flow may beaccelerated and the velocity of the solid particles i.e. carbon and ashentrained in the gas stream may be increased. Accordingly, a largeproportion of the solid particles may be entrained in the second splitstream of raw gas which is directly quenched in the water contained inquench tank 78 located below the gas generator. The actual split of thegas stream between the first and second trains may be controlled by backpressure valves in each line.

The stream of 7.07 million SCF of raw gas stream in line 97 is saturatedwith water as the result of being quenched in quench tank 78 andscrubbed with water in scrubber 92 and spray 98. The gas stream in line97 has the composition shown in column 3 of Table I. 7.07 million SCF ofeffluent gas leaving catalytic water-gas shift converter 101 throughline 102 has the composition shown in column 4 of Table I. After beingcooled by indirect heat exchange below the dew point, the shiftedproduct gas stream in line 27 has the composition shown in Column 5 ofTable I.

About 11,590 GPH of a water dispersion containing about 1 wt. % ofparticulate solids are removed from quench tank 78 by way of line 80 ata temperature of 460° F., and a pressure of 900 psig.

The water-particulate solids dispersions in line 57 and 80 are mixedtogether and resolved in decanter 61 in the manner previously described.About 32,520 GPH of a water dispersion containing about 0.03 wt. % ofparticulate solids are removed from decanter 61 through line 162 at atemperature of 300° F. and a pressure of 300 psig. This stream is passedthrough valve 163 where the pressure is dropped to 20 psig. At least aportion of this stream is converted into steam. The stream passesthrough line 164 and enters flash column 149 below stripping plate 148.

Periodically, blowdown water from gas cooler 33 at a temperature of 564°F. and a pressure of 1150 psig is passed through line 165 and throughvalve 166 where the pressure is reduced to 20 psig. At least a portionof this stream is converted into steam. The stream enters flash column149 through line 167 and then passes through pipe 168 into the spacebelow baffle plate 160. The steam rises up through the column and theunvaporized water falls into chamber 156.

331 GPH of water are separated from the overhead stream from decanter 61in the manner previously discussed and collected in separator 116. Thiswater at a temperature of 140° F. and a pressure of 20 psig is pumpedthrough line 147 and is introduced on to stripping plate 148 of flashcolumn 149. The overhead from flash column 149 is cooled below the dewpoint. Water separates out in separator 116. 1310 GPH of this water at atemperature of 140° F. and a pressure of 20 psig are pumped through line147 on to stripping plate 148 of flash column 149.

29,300 GPH of reclaimed water at a temperature of 259° F. and a pressureof 20 psig are withdrawn from return water side 156 of flash column 149by way of line 182. A portion of the reclaimed water in line 182 isrecycled to gas scrubber 41 in the first train. Another portion of thereclaimed water in line 182 is recycled to orifice scrubber 91 andscrubber 98 in the second train. 3,600 GPH of waste water in receivingside chamber 158 of flash column 149 is withdrawn through line 190 andis discharged from the system.

The process of the invention has been described generally and byexamples with reference to materials of particular compositions forpurposes of clarity and illustration only. It will be apparent to thoseskilled in the art from the foregoing that various modifications of theprocess and materials disclosed herein can be made without departurefrom the spirit of the invention.

                  TABLE I                                                         ______________________________________                                        GAS COMPOSITION - MOLE %                                                      Column No.    1       2       3     4     5                                   Drawing Reference No.                                                                       23      26      97    102   27                                  ______________________________________                                        COMPOSITION                                                                   CO            44.56   49.25   19.16 0.80  1.39                                H.sub.2       39.87   44.06   17.14 35.51 61.96                               CO.sub.2      4.27    4.72    1.83  20.23 35.31                               H.sub.2 O     9.52    --      61.10 42.69 --                                  CH.sub.4      0.36    0.40    0.15  0.16  0.27                                A.sub.r       0.12    0.13    0.05  0.05  0.09                                N.sub.2       0.09    0.10    0.04  0.04  0.07                                H.sub.2 S     1.15    1.27    0.50  0.52  0.91                                COS           0.06    0.07    0.03  --    --                                  ______________________________________                                    

We claim:
 1. In a partial oxidation process for producing gaseousmixtures comprising H₂, CO, H₂ O, entrained particulate carbon and atleast one material from the group CO₂, H₂ S, COS, CH₄, N₂, Ar, and ashby the partial oxidation of a hydrocarbonaceous fuel with a free-oxygencontaining gas optionally with a temperature moderator in a free-flow,non-catalytic gas generator at a temperature in the range of about 1300°to 3000° F. and a pressure in the range of about 1 to 250 atm., coolingthe effluent gas stream from said reaction zone and contacting said gasstream with water in gas quenching or cleaning operations or boththereby removing said entrained particulate carbon and any ash andproducing a clean gas stream and a carbon-water dispersion containingany ash, the improvement comprising: (1) mixing a liquid organicextractant with said carbon-water dispersion, and separating by gravityin a first separation zone a liquid extractant-particulate carbondispersion containing at least one gaseous impurity selected from thegroup H₂ S, NH₃, and CO₂, and a dilute water stream containing carbonand ash and at least one gaseous impurity selected from the group H₂ S,NH₃, and CO₂ ; (2) mixing the extractant-carbon dispersion from (1) witha heavy liquid hydrocarbon; (3) separating the mixture from (2) in adistillation zone into (a) a dispersion of heavy liquid hydrocarbon andparticulate carbon, (b) an overhead gaseous stream comprising H₂ O,organic extractant, and at least one gaseous impurity from the group H₂S, NH₃, and CO₂ ; (4) removing the dispersion of heavy liquidhydrocarbon and particulate carbon from (3a) and introducing same intosaid gas generator as a portion of the feed; (5) cooling and condensingthe overhead gaseous stream from said distillation zone and introducingthe cooled stream into a second separation zone; (6) separating saidcooled stream in said second separation zone into an upper layer ofliquid organic extractant which floats on a lower layer of watercontaining at least one of said gaseous impurities, and an overheadstream of uncondensed gaseous impurities; (7) separating said liquidorganic extractant and recycling same to said first separation zone in(1) as at least a portion of said extractant; introducing the waterseparated in the said second separation zone in (6) on to a horizontalstripping plate spaced within a vertical flash column comprising atleast one stripping plate and first and second bottom chambers separatedby a weir; and wherein each stripping plate contains dispersive meansfor dispersing steam produced below said stripping plate through thewater on said stripping plate, and overflow and downflow means fordischarging stripped water from each plate and into said second bottomchamber; (8) introducing at reduced pressure the water stream containingentrained solids from the first separation zone in (1) into said flashcolumn below the bottom stripping plate and in the space above saidfirst bottom chamber, thereby vaporizing a portion of said water streamand passing the vapors up through said dispersive means in eachstripping plate and through the water contained on each plate therebystripping gases from the water on each plate, and introducing theunvaporized portion of said water stream into said first bottomschamber; (9) removing from said flash column a stream of vaporscomprising H₂ O, hydrocarbons and at least one member of the group H₂ S,NH₃, and CO₂ ; cooling said vapor stream and condensing and separatingin said second separation zone liquid water and liquid hydrocarbon fromthe uncondensed gases; and introducing at least a portion of water fromsaid second separation zone on to a stripping plate in said flashcolumn; (10) removing waste water containing solids from said firstbottoms chamber and discharging same from the system; and (11) removingreclaimed water from said second bottoms chamber and recycling same tosaid gas cleaning operation.
 2. The process of claim 1 provided with thestep of introducing a portion of the water from said second separationzone in step (9) into the gas generator.
 3. The process of claim 1wherein the gaseous impurities from said second separation zone in step(6) and said uncondensed gases in step (9) comprises H₂ S, COS and CO₂and said gas stream is introduced into a Claus process for producingsulfur.
 4. The process of claim 1 wherein blow-down water from a gascooler is simultaneously flashed into the flash column in step (8) belowsaid bottom stripping plate.
 5. The process of claim 1 wherein the waterseparated in (6) is introduced on to the stripping plate in (7) at atemperature in the range of about 80° to 150° F.; the water streamcontaining entrained solids from the separation zone in (1) at atemperature in the range of about 180° to 500° F. and a pressure in therange of about 150 to 1000 psig is passed through a pressure reducingmeans and reduced to a pressure in the range of about 0 to 30 psig priorto being introduced into said flash column in (8) below said strippingplate thereby vaporizing a portion of said water, and the pressure insaid flash column below each stripping plate is about 1 to 3 psiggreater than the pressure in the column above said stripping plate; thestream of vapors removed from the flash column in (9) is at atemperature in the range of about 212° to 275° F.; the water from saidsecond separation zone in step (9) is introduced into the flash columnat a temperature in the range of about 80° to 175° F.; and waste waterin (10) and reclaimed water in (11) are removed at a temperature in therange of about 212° to 275° F.
 6. The process of claim 5 wherein theeffluent gas stream from said reaction zone is cooled in a gas cooler,and blow-down water leaves said gas cooler at a temperature in the rangeof about 300° to 600° F. and is passed through a pressure reducing meansand reduced to a pressure in the range of about 0 to 30 psig prior tobeing introduced into said flash column in (8), thereby vaporizing aportion of of said water.
 7. The process of claim 1 provided with thestep of recycling a portion of the liquid organic extractant separatedin step (6) back to said distillation zone as reflux.
 8. The process ofclaim 1 in which the total amount of liquid organic extractant that ismixed with said carbon-water dispersion in step (1) is in the range ofabout 10 to 200 times the weight of the particulate carbon in thecarbon-water dispersion.
 9. The process of claim 1 in which saidhydrocarbonaceous fuel is a liquid hydrocarbon selected from the groupconsisting of liquefied petroleum gas, petroleum distillates andresidua, gasoline, naphtha, kerosine crude petroleum, asphalt, gas oil,residual oil, tar-sand oil and shale oil, coal derived oil, aromatichydrocarbons (such as benzene, toluene, xylene fractions), coal tar,cycle gas oil from fluid-catalytic-cracking operations, furfural extractof coker gas oil, and mixtures thereof.
 10. The process of claim 1 inwhich said hydrocarbonaceous fuel is a pumpable slurry of a solidcarbonaceous fuel in a liquid carrier from the group consisting ofwater, liquid hydrocarbon fuel, and mixtures thereof.
 11. The process ofclaim 1 in which said hydrocarbonaceous fuel is a gaseous feedstock fromthe group consisting of ethane, propane, butane, pentane, methane,natural gas, coke-oven gas, refinery gas, acetylene tail gas, ethyleneoff-gas, and mixtures thereof.
 12. The process of claim 1 in which saidhydrocarbonaceous fuel is an oxygenated hydrocarbonaceous organicmaterial from the group consisting of carbohydrates, cellulosicmaterials, aldehydes, organic acids, alcohols, ketones, oxygenated fueloil, waste liquids and by-products from chemical processes containingoxygenated hydrocarbonaceous organic materials, and mixtures thereof.13. The process of claim 1 in which said temperature moderator isselected from the group consisting of H₂ O, CO₂, N₂, cooled effluent gasfrom the gas generator, and mixtures thereof.
 14. The process of claim 1in which said free-oxygen containing gas is selected from the groupconsisting of air, oxygen-enriched-air i.e. greater than 21 mole % O₂,and substantially pure oxygen, i.e. greater than about 95 mole % oxygen.15. The process of claim 1 wherein said liquid organic extractant isselected from the group consisting of (1) light liquid hydrocarbon fuelshaving an atmospheric boiling point in the range of about 100° to 750°F., density in degrees API in the range of over 20 to about 100, and acarbon number in the range of about 5 to 16; (2) a mixture ofsubstantially water insoluble liquid organic by-products from an oxo oroxyl process; and (3) mixtures of types (1) and (2).
 16. The process ofclaim 1 wherein said liquid organic extractant is selected from thegroup consisting of butanes, pentanes, hexanes, toluol, naturalgasoline, gasoline, naphtha, gas oil, and mixtures thereof.
 17. Theprocess of claim 1 wherein said heavy liquid hydrocarbon fuel has agravity in degrees API in the range of about -20 to
 20. 18. The processof claim 1 wherein a portion of the water from step (11) is recycled tothe gas generator.
 19. In a partial oxidation process for producinggaseous mixtures comprising H₂, CO, H₂ O, entrained particulate carbonand at least one material from the group CO₂, H₂ S, COS, CH₄, N₂, Ar,and ash by the partial oxidation of a hydrocarbonaceous fuel with afree-oxygen containing gas optionally with a temperature moderator in afree-flow, non-catalytic gas generator at a temperature in the range ofabout 1300° to 3000° F. and a pressure in the range of about 1 to 250atm., cooling the effluent gas stream with water in gas quenching orcleaning operations or both thereby removing said entrained particulatecarbon and any ash and producing a clean gas stream and a carbon-waterdispersion containing any ash, the improvement comprising: (1)introducing into the first stage of a two-stage decanting operation amixture comprising said carbon-water dispersion and a first portion ofliquid organic extractant from (7) in an amount which is sufficient toresolve said carbon-water dispersion; simultaneously introducing intothe second stage of said decanting operation a second portion of saidliquid organic extractant from (7) in an amount sufficient to produce apumpable liquid organic extractant-particulate carbon-water dispersionhaving a solids content in the range of about 0.5 to 9.0 wt.%; andseparating by gravity in a first separation zone a liquidextractant-particulate carbon dispersion containing at least one gaseousimpurity selected from the group H₂ S, NH₃, and CO₂, and a dilute waterstream containing carbon and ash and at least one gaseous impurityselected from the group H₂ S, NH₃, and CO₂ ; (2) mixing theextractant-carbon dispersion from (1) with a heavy liquid hydrocarbon;(3) separating the mixture from (2) in a distillation zone into (a) adispersion of heavy liquid hydrocarbon and particulate carbon, and (b)an overhead gaseous stream comprising H₂ O, organic extractant, and atleast one gaseous impurity from the group H₂ S, NH₃, and CO₂ ; (4)removing the dispersion of heavy liquid hydrocarbon and particulatecarbon from (3a) and introducing same into said gas generator as aportion of the feed; (5) cooling and condensing the overhead gaseousstream from said distillation zone and introducing the cooled streaminto a second separation zone; (6) separating said cooled stream in saidsecond separation zone in (5) into an upper layer of liquid organicextractant with floats on a lower layer of water containing at least oneof said gaseous impurities, and an overhead stream of uncondensedgaseous impurities; (7) separating said liquid organic extractant andrecycling at least a portion of same to said first separation zone in(1) as at leat a portion of said extractant; introducing at least aportion of the water separated in said second separation zone in (6) onto a horizontal stripping plate spaced within a vertical flash columncontaining first and second bottom chambers separated by a weir; andwherein said stripping plate contains dispersive means for dispersingsteam produced below said stripping plate through the water on saidstripping plate and overflow and downflow means for discharging strippedwater from said stripping plate into said second bottom chamber; (8)introducing at reduced pressure the dilute water stream containingentrained solids from the first separation zone in (1) into said flashcolumn below said stripping plate and in the space above said firstbottom chamber, thereby vaporizing a portion of said water stream andpassing the vapors up through said dispersive means in said strippingplate and through the water contained on said plate thereby strippinggases from said water, and introducing the unvaporized portion of saidwater stream into said first bottoms chamber; (9) removing from saidflash column a stream of vapors comprising H₂ O, hydrocarbons and atleast one member of the group H₂ S, NH₃, and CO₂ ; cooling said vaporstream and condensing and separating in said second separation zoneliquid water and liquid hydrocarbon from the uncondensed gases andrecycling at least a portion of said water on to the stripping plate ofsaid flash column; (10) removing waste water containing solids from saidfirst bottoms chamber and discharging same from the system; and (11)removing reclaimed water from said second bottoms chamber and recyclingsame to said gas cleaning operation.
 20. The process of claim 19 inwhich the amount of said liquid organic extractant introduced into thefirst stage of said decanting operation in (1) is in the range of about1.5 to 15 lbs. of extractant per lb. of carbon.
 21. Process for thesimultaneous production of a clean gas mixture comprising H₂ and CO, anda clean H₂ -rich gas stream comprising (1) reacting a hydrocarbonaceousfuel with substantially pure oxygen, in the presence of steam in thereaction zone of a free-flow noncatalytic partial-oxidation gasgenerator at a temperature in the range of about 1300° to 3000° F. andat a pressure in the range of about 1 to 250 atmospheres to produce aneffluent gas stream comprising H₂, CO, H₂ O, solid particles of carbonand ash and at least one gas from the group consisting of CO₂, H₂ S,COS, CH₄, NH₃, N₂ and Ar; (2) splitting the effluent gas stream from (1)into first and second gas streams, and simultaneously processing saidfirst and second gas streams in separate first and second trains; (3)cooling said first gas stream from (2) in said first train by indirectheat exchange with boiler feed water in a gas cooler thereby producingsteam; (4) cleaning the process gas stream from (3) in a first gascleaning zone by contacting same with water, thereby producing apumpable dispersion of solid particles and water; (5) cooling andcondensing water from the process gas stream from (4) thereby producinga clean product gas stream comprising H₂ and CO; (6) cooling andcleaning said second gas stream from (2) by direct contact with water ina second gas cleaning zone thereby removing the solid particlesentrained therein and producing a pumpable dispersion of solid particlesand water while increasing the H₂ O/CO mole ratio of said gas stream toa value in the range of about 2 to 5; (7) reacting together CO and H₂ Oin the gas stream from (6) in a water-gas shift conversion zone, andcooling and condensing water to produce a clean H₂ -rich product gasstream; (8) introducing into a first separtion zone along with a liquidorganic extractant the dispersion of solid particles in water from (4)and (6), and separating a lower layer comprising water, carbon, ash, andgaseous impurities, and an upper layer comprising a dispersion ofparticulate carbon, liquid organic extractant, water and gaseousimpurities; (9) mixing the upper layer from (8) with a heavy liquidhydrocarbon; (10) separating the mixture from (9) in a distillationoperation into (a) a dispersion of heavy liquid hydrocarbon andparticulate carbon, and (b) an overhead gaseous stream comprising H₂ O,organic extractant, and at least one gaseous impurity from the group H₂S, NH₃, and CO₂ ; (11) removing the dispersion of heavy liquidhydrocarbon and particulate carbon from 10 (a) and introducing same intosaid gas generator as a portion of the feed; (12) cooling and condensingsaid overhead gaseous stream (10) (b) and introducing the cooled streaminto a second separation zone; (13) separating said cooled stream insaid second separation zone in (12) into an upper layer of liquidorganic extractant which floats on a lower layer of water containing atleast one of said gaseous impurities; (14) separating said liquidorganic extractant and recycling at least a portion of same to saidfirst separation zone in (8) as at least a portion of said liquidorganic extractant; (15) introducing the water separated in said secondseparation zone in (13) on to a horizontal stripping plate spaced withina vertical flash column containing a first and second bottom chamberseparated by a wier; and wherein said stripping plate containsdispersive means for dispersing steam produced below said strippingplate through the water on said stripping plate, and overflow anddownflow means for discharging stripped water from said stripping plateinto said second bottom chamber; (16) introducing at reduced pressurethe lower layer comprising water, carbon, ash, and gaseous impuritiesfrom the first separation zone in (8) into said flash column below saidstripping plate and in the space above said first bottom chamber therebyvaporizing a portion of said water stream, and passing said vapors upthrough said dispersive means in said stripping plate and through thewater contained on said plate thereby stripping gases from said water,and introducing the unvaporized portion of said water stream into saidfirst bottoms chamber; (17) removing from said flash column a stream ofvapors comprising H₂ O, hydrocarbon, and at least one member of thegroup H₂ S, NH₃, and CO₂ ; cooling said vapor stream and condensing andseparating in said second separation zone liquid water and hydrocarbonsfrom the uncondensed gases; and recycling said water on to the strippingplate of said flash column; (18) removing waste water containing solidsfrom said first bottoms chamber and discharging same from the system;and (19) removing reclaimed water from said second bottoms chamber andrecycling same to said gas cleaning zone in (4) and (6).
 22. In apartial oxidation process for producing gaseous mixtures comprising H₂,CO, H₂ O, entrained particulate carbon and at least one material fromthe group CO₂, H₂ S COS, CH₄, N₂, Ar, and ash by the partial oxidationof a hydrocarbonaceous fuel with a free-oxygen containing gas optionallywith a temperature moderator in a free-flow, non-catalytic gas generatorat a temperature in the range of about 1300° to 3000° F. and a pressurein the range of about 1 to 250 atm., cooling the effluent gas streamfrom said reaction zone and contacting said gas stream with water in gasquenching or cleaning operations or both thereby removing said entrainedparticulate carbon and any ash and producing a clean gas stream and acarbon-water dispersion containing any ash, the improvement comprising:(1) mixing a liquid organic extractant comprising a liquid hydrocarbondistillate substantially comprising about C₃ to about C₁₀ hydrocarbonswith said carbon-water dispersion, and separating by gravity in a firstseparation zone a liquid extractant-particulate carbon dispersioncontaining at least one gaseous impurity selected from the group H₂ S,NH₃, and CO₂, and a dilute water stream containing carbon and ash and atleast one gaseous impurity selected from the group H₂ S, NH₃, and CO₂ ;(2) introducing the liquid extractant-particulate carbon dispersion fromthe first separation zone into the gas generator as a portion of thehydrocarbonaceous fuel; (3) introducing the dilute water stream fromsaid first separation zone at reduced pressure below the bottomstripping plate spaced within a vertical flash column comprising atleast one stripping plate and first and second bottom chambers separatedby a wier, and wherein each stripping plate contains dispersive meansfor dispersing steam produced below said stripping plate through thewater on said stripping plate and overflow and downflow means fordischarging stripped water from plate to plate or into said secondbottom chamber; and wherein said dilute water stream from said firstseparation zone is flashed in the space above said first bottom chamber,thereby vaporizing a portion of said water stream and passing the vaporsup through the dispersive means in each stripping plate and through thewater contained on each plate thereby stripping gases from the water oneach plate, and introducing the unvaporized portion of said water streaminto said first bottoms chamber; (4) removing from said flash column astream of vapors comprising H₂ O, hydrocarbons and at least one memberof the group H₂ S, NH₃, and CO₂ ; cooling said vapor stream andcondensing and separating in a second separation zone liquid water,hydrocarbon liquid or vapor, and uncondensed gases; introducing at leasta portion of the water from said second separation zone on to astripping plate in said flash column; introducing any hydrocarbon liquidseparated in said second separation zone into said first separation zoneor into said gas generator; and removing said uncondensed gases and saidhydrocarbon vapor, if any; (5) removing waste water containing solidsfrom said first bottoms chamber in (3) and discharging same from thesystem; and (6) removing reclaimed water from said second bottomschamber in (3) and recycling same to said gas cleaning operation. 23.The process of claim 22 wherein said uncondensed gases and saidhydrocarbon vapor, if any, removed from said second separation zone instep (4) is introduced into a Claus operation or sent to flare.
 24. Theprocess of claim 22 wherein fresh liquid hydrocarbon distillatesubstantially comprising about C₃ to about C₁₀ hydrocarbons isintroduced into the gas generator as at least a portion of thehydrocarbonaceous fuel.
 25. The process of claim 22 wherein said flashcolumn is equipped with a single plate.